My Operating system is Vista Home Premium 32bit. It came pre-installed on the system. Age of it is about 2.5 years. Would really appreciate it if someone would help me in solving the problem.
The cause appears to be your modem driver. Go to the website of the manufacturer and update the driver.
Huawei Technologies Co., Ltd. USB Modem/Serial Device Driver Description: USB Modem/Serial Device Driver Company: Huawei Technologies Co., Ltd.